Could orthodontic fixed appliances and excess weight affect gingival health in adolescents?


The aim of this study was to evaluate the impact of being overweight or obese while wearing orthodontic fixed appliances on the prevalence of gingivitis in adolescents.


A total of 334 adolescents, aged between 12 and 18 years, were recruited from 3 public schools in Cuiabá, Brazil. Participants were divided in dichotomized categories of body mass index (BMI) (under and normal weight or overweight and obesity) and fixed orthodontic appliance usage (yes or no). Gingival inflammation was evaluated by Löe & Silness index. Socioeconomic status was determined by the criteria of the Brazilian Association of Research Companies, and sugar consumption was assessed by a questionnaire of dietary habits. The statistical analysis was performed with P <0.05 considered significant.


In a multivariate linear regression model, gingivitis was directly related to BMI (%) variation and orthodontic appliance use. In addition, excess weight seemed to be 2 times more relevant in predicting gingivitis than orthodontic fixed appliance usage. A strong positive correlation was observed between BMI (%) variation and gingival index (ρ = 0.97, P <0.001).


Orthodontic fixed appliance usage and excess weight were associated with increased gingivitis in adolescents; BMI (%) variation was the most significant predictor of gingival inflammation.


  • Orthodontic treatment increases gingival inflammation in normal-weight patients.

  • The co-occurrence of orthodontic treatment and excess weight increases gingivitis.

  • Gingival index is strongly correlated with the variation of body mass index (%) in adolescents.

  • The variation of body mass index (%) is a more important predictor to gingival inflammation than orthodontic appliance usage.

The consumption of a high-sugar and high-fat diet associated with sedentary lifestyle has reached epidemic proportions worldwide, leading to increases in body mass index (BMI). This situation affects all ages and socioeconomic groups and predisposes to the development of chronic and debilitating diseases, such as diabetes, cardiovascular diseases, hypertension, osteoarthritis, respiratory difficulties, and musculoskeletal problems. In Brazil, overweight and obesity affect between 47.5% and 56.3% of the population, according to geographic area and urbanization levels.

Because of behavior changes, with the consequent adoption of unhealthy eating and hygiene habits, adolescence is a period marked by concurrent risk factors for the development of overweight or obesity and oral diseases, especially dental caries and gingivitis. Moreover, this is the preferred life stage for orthodontic treatments, introducing brackets, bands, and other accessories on dental surfaces that favor the biofilm accumulation and hamper toothbrushing and flossing performances.

Whereas fixed orthodontic appliances might contribute to the development of white spot lesions on the enamel in adolescents, , the association of BMI with gingival inflammation is still controversial. Therefore, the aim of this study was to evaluate gingival inflammation of adolescents, regarding orthodontic fixed appliance usage and different weight categories. The influence of sociodemographic variables and sugar consumption were considered for data analysis.

Material and methods

This cross-sectional study was approved by the Human Research Ethics Committee of the University of Cuiabá in accordance with the ethical standards of the Declaration of Helsinki.

The sample of participants was obtained from 3 public schools in Cuiabá, Brazil. The parents of the adolescents received information concerning the aims of the study and signed a statement of informed consent to the inclusion of material pertaining to their children, with the maintenance of anonymous information and no identification of their acknowledgment via the paper. This study included all 12-18-year-old students without systemic diseases who were available to collaborate with the research.

The sample size of each weight category was calculated for a confidence interval (CI) of 95%, β error of 20%, and clinically significant differences of 0.15 for gingival inflammation. The minimum number of 339 and 84 participants were determined for underweight or normal weight and overweight or obesity categories, respectively, with a basis on the standard deviation values (0.34) for both groups determined with a basis on a subsample of this study (n = 111).

A trained investigator evaluated the body mass (kg) and height (m) of participants with a digital scale (UM061 Body Fat/Body Water Monitor; Tanita Corporation, Arlington Heights, Ill) and a stadiometer (WCS; Cardiomed, Curitiba, Brazil), respectively. Body mass and height were used to calculate the BMI (kg/m 2 ) of each adolescent to classify them in 2 different weight categories, according to the percentiles of BMI-for-age (5-19 years) z-scores for boys and girls, as follows: (1) underweight or normal weight (up to 85th percentile), and (2) overweight or obese (over 85th percentile). The maximum values of BMI for normal weights were identified in the curves for calculating the percentage of weight variation of each participant, by the application of the following formula:

<SPAN role=presentation tabIndex=0 id=MathJax-Element-1-Frame class=MathJax style="POSITION: relative" data-mathml='%BMIvariation=BMIindividual−BMImaximumnormalweightBMImaximumnormalweight×100′>%????????????=???????????????????????????????????????????????????????×100%BMIvariation=BMIindividual−BMImaximumnormalweightBMImaximumnormalweight×100
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Mar 9, 2020 | Posted by in Orthodontics | Comments Off on Could orthodontic fixed appliances and excess weight affect gingival health in adolescents?
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